Magnetotransport studies of the Sb square-net compound LaAgSb${}_2$ under high pressure and rotating magnetic fields

Abstract

Square-net-layered materials have attracted attention as an extended research platform of Dirac fermions and of exotic magneto-transport phenomena. In this study, we investigated the magneto-transport properties of LaAgSb${}_2$, which has Sb-square-net layers and shows charge density wave (CDW) transitions at ambient pressure. The application of pressure suppresses the CDWs, and above a pressure of 3.2 GPa, a disordered phase with no CDWs is realized. By utilizing a mechanical rotator combined with a high-pressure cell, we observed the angular dependence of the Shubnikov-de Haas (SdH) oscillation up to 3.5 GPa and confirmed the notable two-dimensional nature of the Fermi surface. In the disordered phase, we also observed a remarkable field-angular-dependent magnetoresistance (MR), which exhibited a "butterfly-like" polar pattern. To understand these results, we theoretically calculated the Fermi surface and conductivity tensor at the disordered phase. We showed that the SdH frequency and Hall coefficient calculated based on the present Fermi surface model agree well with the experiment. The transport properties in the disordered phase are mostly dominated by the anisotropic Dirac band, which has the highest conductivity owing to linear energy dispersions. We also proposed that momentum-dependent relaxation time plays an important role in the large transverse MR and negative longitudinal MR in the disordered phase, which is experimentally supported by the considerable violation of Kohler's scaling rule. Although quantitatively complete reproduction was not achieved, the calculation showed that the elemental features of the butterfly MR could be reasonably explained as the geometrical effect of the Fermi surface.

12 pages, 9 figures

References in corpus (12)

• Quantum ESPRESSO: a modular and open-source software project for quantum simulations of materials
• Advanced capabilities for materials modelling with Quantum ESPRESSO
• Quantum Hall effect in a bulk antiferromagnet EuMnBi${}_2$ with magnetically confined two-dimensional Dirac fermions
• Observation of two-dimensional Fermi surface and Dirac dispersion in YbMnSb${}_2$
• Bulk quantum Hall effect of spin-valley-coupled Dirac fermions in a polar antiferromagnet BaMnSb${}_2$
• Revealing extremely low energy amplitude modes in the charge-density-wave compound LaAgSb${}_2$
• Interlayer electronic transport in CaMnBi${}_2$ antiferromagnet
• Thermal expansion and magnetostriction of pure and doped RAgSb2 (R = Y, Sm, La) single crystals
• Phonon limited thermoelectric transport in Pb
• Evidence for nesting driven charge density waves instabilities in a quasi-two-dimensional material: LaAgSb2
• Origin of the butterfly magnetoresistance in ZrSiS
• Successive destruction of charge density wave states by pressure in LaAgSb${}_2$

Cited by in corpus (5)

• Electronic band structure and surface states in Dirac semimetal LaAgSb${}_2$
• Observation of superconductivity and its enhancement at the charge density wave critical point in LaAgSb${}_2$
• Coexistence of Dirac fermion and charge density wave in square-net-based semimetal LaAuSb2
• Phonon-mediated superconductivity in the Sb-square-net compound LaCuSb${}_2$
• Crystal Growth and anisotropic magneto-transport properties of semimetallic LaNiSb3